Shoe construction



Jan. 21, 1969 A. P. BLANK 3,422,551

SHOE CONSTRUCTION Filed March 16, 1965 Jzzmsvz for flaralz Z KW yf yajww M United States Patent Office 3,422,551 Patented Jan. 21, 1969 3,422,551 SHOE CONSTRUCTION Aaron P. Blank, Dorchester, Mass., assignor to Jacob S. Kamborian, West Newton, Mass. Filed Mar. 16, 1965, Ser. No. 440,088 U.S. CI. 36-77 Int. Cl. A43b 23/17 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to shoe construction and more particularly to compositions, stage products and methods for making shoes with selected portions of the upper stiffened to resist deformation.

In shoe manufacture it is customary to stiffen portions of the upper, typically toe and heel portions. In copending application Ser. No. 366,513, filed May 11, 1964, entitled Machine and Method for Making Shoes, now U.S. Patents 3,342,624, dated Sept. 19, 1967, improved methods and apparatus are disclosed which apply stiffener material as a hot melt liquid by means of a stencil and doctor, the liquid being dispensed through the stencil openings onto shoe upper material and metered by scraping with a doctor blade or the like. Preferably the upper material is coated at room temperature in a substantially flat, unlasted position. When applied to the bottom or underside of a shoe vamp which converges towards its toe end, the stiffener composition preferably is applied with an area of substantially uniform thickness but with a tapered or feathered edge rearward of the toe end of the vamp, and with a mound of greater thickness intermediate said uniform area and preferably near the toe end along the longitudinal axis of the vamp. The stencil has an opening of a contour and thickness corresponding to the desired contour and thickness of stiffener composition desired on the shoe upper part.

It is the principal object of the present invention to provide improved hot-melt stiffener composition for use in the above stencil method, improved methods of stiffening shoe parts therewith, and stage products incorporating the same for use in shoe manufacture. Further objects include provision of stiffener compositions adhesive to and compatible with a wide variety of shoe upper materials, which can readily be provided with a variation of stiffness as desired for inclusion in varying types of shoe designs, which is non-tacky at ambient conditions, readily moldable without melting or adhesiveness at hot-shoe lasting temperatures, for example upper steaming temperatures of about 170 to 200 F., and which is tough and durable in use. Other and further objects and advantages will be apparent from the following description.

In accordance with one aspect of this invention, the improved stiffening composition comprises an intimate, homogeneous, substantially non-volatile mixture of (a) a copolymer of ethylene and a minor mol proportion of a comonomer selected from the group consisting of vinyl acetate, ethyl acrylate and isobutyl acrylate, the copolymer having a softening point (ring and ball, ASTM E-28) of at least about 170 F., and preferably above 200 F., and having a melt index, according to ASTM D-1238-57T, of

at least 20; and (b) a Wax compatible therewith having a melting point of at least about 190 F. and a penetration less than about 25, and preferably less than 3, as determined by ASTM D-1321 using grams for 5 seconds at 77 F., said wax comprising from about 5 to 50% of the combined weight of wax and copolymer.

While the above copolymer has desirable toughness, compatibility, and melt properties useful for hot-melt stiffening of shoes, being substantially superior to pure polyethylene, it does not have the stiffness generally required. However, it has been found that the defined waxes increase the stiffness, generally in proportion to the amount of wax employed, without causing objectionable brittleness. Thus a series of products of graduated stiffnesses are readily provided by increasing the ratio of wax to copolymer. Excessive wax should be avoided since it can result in undue loss of film and strength characteristics.

For use herein, a wax is considered to be compatible if it can be dispersed in the copolymer without chemical reaction and without separation in the solid or liquid state of the resulting mixture. Clarity is not essential. The compatibility of a given wax can be increased by use of a third ingredient which is chemically inert but which is compatible with both the wax and copolymer, and use of such third ingredients Where desirable is expressly contemplated. However, as stated above, the final composition should be devoid of ingredients which volatilize significantly when the composition is melted. Suitable compatibilizing agents include low molecular weight thermoplastic hydrocarbon resins, for example Super Beckacite 2000 of Reich-hold Chemicals, Inc., understood to be a pure phenolic resin. Other mutually compatible, chemically inert ingredients can also be used.

Examples of commercial copolymers useful according to this invention are the ELVAX resins of the Du Pont Company, Numbers 420, 240, 220, 210, 150, 40 and EOD 3616-8, understood to be copolymers of ethylene with from 17 to 42 mol percent vinyl acetate and having melt indexes from about 22 to 750; the DQDA resins of Union Carbide Corporation, Numbers 6225, 3860, 7268, 3269, understood to be copolymers of ethylene with from 18 to 28.5 mol percent vinyl acetate and having melt indexes from about 20 to 350; the QX resins numbered 2230.2, 2230.3, 2230.4 and 2230.5 of the Dow Chemical Company, understood to be copolymers of ethylene with about 20 to 40 mol percent isobutyl acrylate and having melt indexes from about 20 to 250; and QX resin 3488.8 understood to be a copolymer of ethylene with about 20 mol percent ethyl acrylate and having a melt index of about 70.

Waxes useful as stiffeners in the present invention include both natural and synthetic waxes compatible with the copolymer and melting above about F. and being generally hard with penetrations less than about 25 and preferably less than 3. Commercial examples are given in the following table:

TABLE I Designation Type Penetra- M. P. tion F.)

(1) Parafiint RG Fischer-Tropsch 1. 5 214 Parafiin. (2) DQWA 0300 2 Crysgalline Poly- 0. 5 270 o e n. (3) Fortex Microerystalline 3-4 -200 (4) Albaplex SL L Plastorner 1-2 200-205 (5) Cardis N o. 10 0-1 212-216 (6) Cardis No. 935 2. 5 205-208 (7) Cardis N0. 8 3 do 1-2 205-210 (8) Polymekon 3 Petroleum wax... 0-3 195-205 (9) Petrolite PE100 4 Microcrystalline 2-3 195-200 (10) Petrolite C7500 -do l-3 205-215 (11) Petrolite R50 4 do 2 190-200 1 Moore & Munger, Inc.

2 Union Carbide Corporation.

3 Warwick Wax Division, Western Petrochemical Corp. 4 Bareco Wax Division, Petrolite Corporation.

Examples of compositions according to this invention are given below wherein parts are by weight and wherein Example 1 is preferred, with variation in wax content where desired to vary stiffness.

The copolymer-wax compositions can be prepared in any suitable way. For example, they can be melted, mixed and then solidified for storage. In use, they are supplied to an applicator, melted, fed to the stencil opening and therethrough onto the underside of a generally cold shoe upper part, excess, if any, being scraped off the stencil surface by doctor, the composition allowed to solidify, and the shoe part and hardened stiffener removed from beneath the stencil.

This invention may be further understood by reference to the accompanying drawing wherein:

FIG. 1 is a longitudinal vertical fragmentary section of a machine for applying stiffener composition to a shoe upper material;

FIG. 2 is a plan view of a shoe part to which stiffener composition has been applied;

FIG. 3 is a transverse section on the line 33 of FIG. 2; and

FIG. 4 is a longitudinal section on the line 4-4 of FIG. 2.

FIGS. 1-4 correspond to FIGS. -13, respectively, of the above-described copending US. Patent No. 3,342,624 to which reference is made for detailed description.

The apparatus illustrated in FIG. 1 comprises a work support 1 having a depression 2, a stencil 3 having opening 4 which tapers to a feather edge 5, and an applicator 6, having a doctor 7.

Applicator 6 comprises a bar 8 having a transverse bore 9 the ends of which are sealed, opening 10 communicating with bore 9 into which nipple 11 is threaded, and a plurality of orifices 12 communicating with bore 9. Stifiener material is fed in molten form from a reservoir (not shown) through nipple 11 and opening 10 to bore 9 and thence through feed orifices 12. The flow of liquid is controlled by rotatable control valve 13. Applicator 6 is mounted for horizontal movement as indicated by the arrow, FIG. 1.

Work support 1 is mounted for horizontal and vertical movement as shown by the arrows in FIG. 1 and has a plurality of locating pins 14 yieldably mounted in cylinders 15, the pins being so located as to contact the marginal edge of the upper material 16 (FIG. 2).

In operation, work support 1 is moved horizontally from beneath fixed stencil 3, shoe upper material or part 16 is placed over support 1 in peripheral contact with pins 14, and suction is applied through holes (not shown) in support 1 to hold the material in place and within depression 2. The support is then moved under the stencil and upwardly to the position shown in FIG. 1, the material 16 being clamped between stencil 3 and support 1. Applicator 6 is then moved to the forward position shown in FIG. 1 and valve 13 is opened to dispense molten sifiener material through orifices 12. As molten liquid is dispensed, applicator 6 and doctor 7 is scraped across the stencil opening 4 to fill the same, excess liquid being scraped into a waste receptacle (not shown). Support 1 is then moved downwardly and then horizontally from beneath the stencil 3, suction inactivated and part 16,

with solidified stiffener 17 adhering thereto, removed. The resulting stage product is shown in FIGS. 2-4 and comprises upper material 16, in the case illustrated, a shoe vamp =with marginal edges converging toward its toe end, and, fused directly to the underside thereof, stiffener composition 17 having an area of substantially uniform thickness, a tapering rearward edge 18 and, located near the toe end along the longitudinal centerline of the vamp, a thickened intermediate portion 19. Thickened portion 19 serves to provide greater stiffness and resistance to deformation at a point of greatest anticipated stress.

The above coated shoe upper par-t constitutes a stage product useful in the lasting of shoes. The product is sufficiently flexible that it can be stressed cold to provide simple shapes. For more complex shapes, the upper part can be heated, for example steamed at about 200 F. as often done in lasting operations, and the product molded over a last or other form.

It is an advantage of the present invention that the stiffener composition, and stage products containing the same, are readily moldable by conventional technique without melting or becoming adhesive. Thus, no covering during lasting or in use is required.

Stiffener compositions according to this invention are further advantageous in that they are compatible with most shoe upper materials. They are not rendered tacky or non-adhering for example, by absorption of oil from leather, and can therefore be used with oily leathers without covers or other protection. Also, they possess desirable molding and melt characteristics. While they melt above lasting and use temperatures, the melting temperatures are sufiiciently low that little difficulty has been encountered with gas formation, for example, from moisture present in the shoe upper material being stiffened.

It should be understood that the foregoing description is for the purpose of illustration and that the invention includes all modifications falling within the scope of the appended claims.

I claim:

1. A meltable stiffener composition for hot-melt application to selected portions of shoe upper material comprising an intimate non-volatile mixture of (a) a copolymer of ethylene and a minor mol proportion of a comonomer selected from the group consisting of vinyl acetate, ethyl acrylate and isobutyl acrylate, said copolymer having a softening point of at least about 170 F. and having a melt index of at least about 20, and

(b) a wax compatible with said copolymer having a melting point of at least about F. and a penetration of less than about 25, said wax constituting from about 5 to 50% by the combined weight of wax and copolymer.

2. A stiffener composition according to claim 1 wherein said wax has a penetration less than about 3 and said copolymer has a softening point of at least 200 F.

3. Shoe upper material having fused to selected portions thereof a stiffener composition comprising an intimate non-volatile mixture of a copolymer of ethylene and a minor mol proportion of a comonomer selected from the group consisting of vinyl acetate, ethyl acrylate and isobutyl acrylate, said copolymer having a softening point of at least about 170 F. and having a melt index of at least about 20, and a wax compatible with said copolymer having a melting point of at least about 190 F. and a penetration of less than about 25, said wax constituting from about 5 to 50% by the combined weight of wax and copolymer.

4. Shoe upper material according to claim 3 wherein said wax has a penetration less than about 3 and said copolymer has a softening point of at least 200 F.

5. Shoe upper material having fused to selected portions thereof a stiffener composition comprising an intimate non-volatile mixture of a copolymer of ethylene and a minor mol proportion of a comonomer selected from the group consisting of vinyl acetate, ethyl acrylate and isobutyl acrylate, said copolymer having a softening point of at least about 170 F. and having a melt index of at least about 20, and a wax compatible with said copolymer having a melting point of at least about 190 F. and a penetration of less than about 25, said wax constituting from about 5 to 50% by the combined weight of wax and copolymer, said upper material being substantially fiat and having a toe portion with top and bottom surfaces, said stiffener composition being fused directly to the bottom surface of said toe portion, said upper and stiffener composition being moldable without melting at temperatures between about 170 and 200 F.

6. Shoe upper material according to claim 5 wherein said fused stiffener material has an area of substantially uniform thickness, a feathered edge rearward of the toe end and a thickened intermediate portion within said area along the longitudinal centerline of said toe portion.

7. The method of stiffening a selected portion of a shoe part which comprises providing a stiffener composition comprising an intimate mixture of a copolymer of ethylene and a minor rnol proportion of a comonomer selected from the group consisting of vinyl acetate, ethyl acrylate and isobutyl acrylate, said copolymer having a softening point of at least about 170 F., and having a melt index of at least about 20, and a wax compatible with said copolymer having a melting point of at least about 190 F. and a penetration of less than about 25, said wax constituting from about 5 to 50% by the combined weight of wax and copolymer, melting said composition, depositing it onto said part, and allowing said composition to solidify.

8. The method according to claim 7 wherein said wax has a penetration less than about 3.0 and said copolymer has a softening point of at least 200 F.

References Cited UNITED STATES PATENTS 1,926,161 9/1933 Mellerio 3677 2,133,346 10/1938 Diller et al. 12146 XR 3,025,167 3/1962 Butler 26028.5 3,155,631 11/1964 Zapp 26028.5 3,189,573 6/1965 Oken 26028.5 3,215,657 11/ 1965 Beresniewicz 26028.5

PATRICK D. LAWSON, Primary Examiner.

H. H. HUNTER, Assistant Examiner.

US. Cl. X.R. 

25. THE WAX IS ADDED TO THE COPOLYMER TO INCREASE ITS STIFFNESS PROPERTIES. 